Return-Path: Received: from imf04aec.mail.bellsouth.net ([205.152.59.52] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2779440 for flyrotary@lancaironline.net; Mon, 01 Dec 2003 13:50:59 -0500 Received: from TOSHIBAjhr ([209.214.14.179]) by imf16aec.mail.bellsouth.net (InterMail vM.5.01.06.05 201-253-122-130-105-20030824) with SMTP id <20031201172700.SJCV1876.imf16aec.mail.bellsouth.net@TOSHIBAjhr> for ; Mon, 1 Dec 2003 12:27:00 -0500 From: "John Slade" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Ducts Vs Diffuser - Cooling (a bit long) Date: Mon, 1 Dec 2003 12:27:02 -0500 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0000_01C3B806.6C3A4AE0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0000_01C3B806.6C3A4AE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hi Ed, I have to wonder what do you do when you're not thinking about airplanes? Sleep? Thanks for you're interesting discourse on diffusers. This leads me to a question that's been in my mind for some time..... My NACA duct (pusher) leads into a plenum which is constrained by the sizes of the cowl and radiator. The forward end of the rad is only a couple of inches behind the firewall, so the "diffuser" is pretty abrupt. I've been wondering if I should insert a fiberglass panel to make the diffuser angle much less, but this would block out the first foot or so of the rad. I could leave a gap at the end so the air has a way to get at the first part of the rad, but blocking the rad like this seems counter intuitive. Note that I have a cowl flap at the rear of the plenum which will allow air to bypass the rad and flow directly out of the back of the cowl. This should allow me to experiment with the pressure and airflow inside the plenum. Also, in case you'd like to comment an how they might work, I have ducts leading from the plenum to diffusers on the intercooler and ac condenser, plus a duct for the turbo intake air. Finally I have a big fan on the underside of the rad. The sketch at http://kgarden.com/cozy/diffuser.jpg might help explain what I mean. The upper picture shows what I've got. The lower one shows what I could do, and also shows the cowl flap open. The question is - should I do this? You're thoughts and comments would be appreciated. Regards, John PS I posted this with the picture attached, but it didnt appear on the list. Sorry if it turns up twice. ------=_NextPart_000_0000_01C3B806.6C3A4AE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hi=20 Ed,

I have=20 to wonder what do you do when you're not thinking about airplanes?=20 Sleep?

Thanks=20 for you're interesting discourse on diffusers. This leads me to a = question=20 that's been in my mind for some time.....

My=20 NACA duct (pusher) leads into a plenum which is constrained by the sizes = of the=20 cowl and radiator.

The=20 forward end of the rad is only a couple of inches behind the firewall, = so the=20 "diffuser" is pretty abrupt. I've been wondering if I should insert a = fiberglass=20 panel to make the diffuser angle much less, but this would block out the = first=20 foot or so of the rad. I could leave a gap at the end so the air has a = way to=20 get at the first part of the rad, but blocking the rad like this seems = counter=20 intuitive. Note that I have a cowl flap at the rear of the plenum = which=20 will allow air to bypass the rad and flow directly out of the back of = the cowl.=20 This should allow me to experiment with the pressure and airflow inside = the=20 plenum.

Also, in case you'd like to comment an how they = might work, I=20 have ducts leading from the plenum to diffusers on the intercooler and = ac=20 condenser, plus a duct for the turbo intake air. Finally I have a = big fan=20 on the underside of the rad.

The sketch at http://kgarden.com/cozy/dif= fuser.jpg=20 might help explain what I mean. The upper picture shows what = I've=20 got. The lower one shows what I could do, and also shows the cowl flap=20 open.

The=20 question is - should I do this? You're thoughts and comments would be=20 appreciated.

Regards,

John

PS I posted this with the picture = attached, but=20 it didnt appear on the list. Sorry if it turns up=20 twice.

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